Janet, Randy and Rebbie Jackson accuse the executors of a "relentless" negative media campaign and say they have been barred from visiting their 82-year-old mother or Jackson's children.

"The effect of that notice not only is to damage fundamental family relationships, it is also to isolate Katherine Jackson from anyone questioning the validity of Michael's will," reads the statement by Janet Jackson's attorney, Blair G. Brown, released on behalf of Janet, Randy and Rebbie Jackson.

They say they will continue to contest Michael Jackson's will because "the executors have never explained how Michael could have signed his will in California on a date that irrefutable evidence establishes that he was in New York."

Representatives for the executors of the will did not immediately respond to calls and emails requesting comment.